Process for the manufacture of a row of linking components for a slide fastener

ABSTRACT

In a known process and apparatus for the production of continuous row of linking components for a slide fastener, using a plastic thread, the plastic thread is shaped into a spiral over and between a series of studs by means of a thread guide. One of the ends of each whorl of the spiral is crushed by means of a punch to form a linking component, while holding the corresponding whorl between the studs. The invention provides the improvement in that, on the crushing-point side of each whorl, the corresponding portion of the thread is stretched out rectilinearly beyond the crushing point and facing the corresponding side face of the thread guide. The required point of the thread is then crushed against the thread guide, which is used as an anvil, the punch used being independent of the other working tools, and the folding back of the corresponding portion of the thread being performed only after the crushing has been carried out.

Sept. 3, 1974 JAKOB 3,838,707

YROCESS FOR THE MANUFACTURE OF A ROW OF LINKING COMPONENTS FOR A SLIDE FASTENER Original Filed Oct. 5. 1971 2 Sheets-Sheet 1 Fig. 3

H. JAKOB 3,833,707 PROCESS FOR THE} MANUFACTURE OF A ROW OF LINKING Sept. 3,1974

COMPONENTS FOR A SLIDE FASTENER 1971 2 Sheets-Sheet 2 Original Filed Oct.

United States Patent O M PROCESS FOR THE MANUFACTURE OF A ROW OF LINKING COMPONENTS FOR A SLIDE FASTENER Horst Jakob, Choisy-le-Roi, France, assignor to Societe Financiere Francaise de Licences et Brevets, Choisyle-Roi, France Original application Oct. 5, 1971, Ser. No. 186,612, new Patent No. 3,787,164. Divided and this application July 25, 1973, Ser. No. 382,584

Int. Cl. B29d 5/00 US. Cl. 264-285 1 Claim ABSTRACT OF THE DISCLOSURE In a known process and apparatus for the production of a continuous row of linking components for a slide fastener, using a plastic thread, the plastic thread is shaped into a spiral over and between a series of studs by means of a thread guide. One of the ends of each whorl of the spiral is crushed by means of a punch to form a linking component, while holding the corresponding whorl between the studs. The invention provides the improvement in that, on the crushing-point side of each whorl, the corresponding portion of the thread is stretched out rectilinearly beyond the crushing point and facing the corre sponding side face of the thread guide. The required point of the thread is then crushed against the thread guide, which is used as an anvil, the punch used being independent of the other working tools, and the folding back of the corresponding portion of the thread being performed only after the crushing has been carried out.

This application is a division of Application Serial No. 186,612, filed Oct. 5, 1971, now Pat. No. 3,787,164 granted Jan. 22, 1974.

This invention relates to the manufacture of continuous rows of linking components for a slide fastener, using a plastic thread.

More specifically, it relates to a manufacturing process which consists of shaping such a thread into a spiral between a series of studs and crushing one of the ends of each whorl in order to constitute a linking component at the same time holding the corresponding whorl between two studs.

In order to be able to obtain this latter result, the notches between the studs must therefore be narrower in width than the linking components formed by crushing the thread. The thread is positioned between the studs by means of a thread-guide to which a to-and-fro movement is imparted in a direction parallel to its axis so as to place the thread first in one direction then in the other inside each notch. During this operation, the stud support is kept still, but a movement equal to the space between two of the notches is subsequently imparted to it to bring the next notch in front of the thread-guide.

Thus, on one of the sides of the spiral the thread is folded around studs which thus keep this spiral in position. On the opposite side, this spiral is held in the way already mentioned, i.e., by holding the flattened portion formed by each of the linking components made by crushing the thread.

In this connection, it should be noted that the punch used for this purpose consists of the thread-guide itself, which has several disadvantages.

One of these is that this makes it necessary to arrange for this part to undergo a complicated movement. In fact, its to-and-fro movement must be combined with a movement in a direction parallel to one of the spokes of the toothed plate when the thread is crushed, and a complementary return movement.

Patented Sept. 3, 1974 Another disadvantage is that the strength of the pressure which can be exerted with the crushing punch is limited by the fact that the latter is integral with the threadguide.

Yet another disadvantage is the fact that the crushing of the thread occurs on the edge of a portion of thread raised at right angles. Now, this is detrimental to the obtention of linking components with exactly the required profile.

This is why this invention covers a new manufacturing process of the same kind, but which is so designed as to eliminate the disadvantages listed above.

This process is characterized in that on the crushingpoint side of each whorl, the thread is stretched out rectilinearly beyond this point, and facing the corresponding side face of the thread guide, and in that the required point along the thread is then crushed against this part, which is thus used as an anvil, while the punch used is independent of the other working tools, the thread being folded back subsequently.

This invention also covers a device specially designed for putting this manufacturing process into operation. A form of embodiment of this device is described below, together with an example of the operation of this process. This description is given with reference to the drawing attached as an indication only, wherein:

FIG. 1 is a partial sectional view of the manufacturing device in accordance with the invention, shown after the thread has been folded back;

FIG. 2 is a similar view showing this device at the moment when the thread-guide begins to stretch out a portion of thread rectilinearly;

FIGS. 3 to 5 are similar sectional views illustrating the later phases of manufacture; and

FIGS. 6 to 8 are partial perspective views of the same device, showing it in the positions already illustrated in FIGS. 1, 4 and 5.

The device shown comprises a circular plate 1 equipped with studs 2 around its periphery. The width 2 of each of the latter corresponds to the required distance between two successive whorls of the spiral to be made out of a plastic thread 3 to form a continuous row of linking components for a slide fastener.

Facing the plate 1 there is a thread-guide 6 to which a to-and-fro movement is imparted in accordance with arrows F1 and F2 in a direction parallel to the axis of the toothed plate 1.

The thread-guide 6 is transpierced from side to side by a hole 7 oriented radially in relation to the plate 1. The plastic thread 3 is treaded through this hole so as to be placed by the thread-guide in the notches between the teeth of the plate, as will be described in detail further on.

When the device is in operation, the thread is, of course, made to slide in the direction of the arrow F3 inside the hole 7 as the spiral is formed. Moreover, the thread-guide includes a brake designed to prevent any possibility of the thread going backwards. This brake consists of a pushrod 8 subjected to the action of a spring 9 and of which the end in contact with the thread is chamfered to prevent the latter going backwards, while allowing it to slide in the direction F3.

The plate 1 is mounted to rotate around its axis and is fitted with drive means capable of intermittently imparting to it an angular movement in the direction of the arrow F4, equal to the width E between two successive notches 10 in its periphery so that each of these is successively brought opposite the hole 7 in the thread-guide 6. Synchronization of the latters drive means and those of the toothed plate 1 is such that the latters intermittent angular movement occurs after a whorl of the spiral has been formed.

Finally, a punch 11 is provided, designed to crush the thread 3 which can later form a linking component. This punch offers the peculiarity that it consists of a part which is independent of the other components of this device.

This punch 11 is positioned facing the face of the plate 1 towards which the thread 3 is first of all drawn. This punch has a simple to-andfro movement imparted to it in a direction F5 parallel to the plate 1 and in the radial plate of the latter which passes through the outlet of the hole 7.v

The end of this punch is positioned facing the corresponding flat face 6a of the thread-guide which can thus serve as an anvil when the thread 3 is crushed.

The drive means of this punch and those of the threadguide are so synchronized that crushing takes place before folding of this portion of thread.

Moreover, by means of the particular mode of arrangement of this device, the manufacturing process covered by the invention is operated in the following manner.

After a whorl has been formed, the thread-guide 6 is in the maximum up position shown in FIG. 1. At that moment, an angular movement E is imparted to the toothed plate 1 so as to bring its next empty notch opposite the hole 7 in the thread-guide. The effect of this movement is to exert a pull on the thread 3 which comes against the corresponding stud 2 of the plate, there forming a linking portion 12. between two successive whorls of the spiral.

After this movement, the thread-guide 6 is moved in the direction of the arrow F1, as shown in FIGS. 2 and 3. During this movement, the thread-guide exerts a pull on the plastic thread 3 which it deposits in the corresponding notch 10.

However, the mode of arrangement is such that the thread-guide continues its movement until it is in the position shown in FIG. 4 and is situated at a certain distance from the crushing punch 11.

In this position, the thread-guide has thus drawn a considerable length of thread beyond the latter, rectilinearly. This length extends facing the corresponding fiat face 6a of the thread-guide, which is parallel to the axis of the toothed plate.

Immediately afterwards, the punch 11 is moved in the direction of the arrow F5 towards the thread-guide 6. In these circumstances, this punch crushes the thread 3 against the corresponding face 6a of this part, which then serves as an anvil. This crushing occurs at point 13 and the section of the thread at this point is thus flattened and will later form one of the linking components of the row under manufacture.

Then, the thread-guide 6 again has a movement imparted to it, but in the opposite direction F2, the result of which is to exert a pull on the thread in this direction. This pull causes the corresponding portion of the thread to fold at its point of crushing 13.

This operation is facilitated by the presence of the brake 8. The whorl so formed is then held in the corresponding notch in the plate 1 against the pull exerted on the thread due to the fact that the flattened portion formed by the linking head 13 comes up against the corresponding bottom face of the plate 1.

The thread-guide then continues its movement until it reaches its maximum up" position shown in FIG. I, after which the device is again ready to carry out a further working cycle as previously described.

Because of their particular design, the process and the device covered by the invention offers a number of advantages, in particular the following:

1. The shaping of the linking components is effected under optimum conditions, as the crushing of the thread is done on a rectilinear portion thereof. Moreover, a substantial length of thread is held rectilinearly against the corresponding face of the thread-guide beyond the crushing point. In these circumstances, the thread can spread out perfectly flat against the flat face 6a of the threadguide which constitutes an anvil.

This consequently makes it possible to obtain the shape required for each linking component very precisely. Now, the same does not apply to the former process mentioned previously, as in that process, the crushing of the thread is always done next to a folded, or at least partly bent, portion of thread. 7 i

2. The crushing punch 11 is completely independent of the other components of this device.

Because of this, much stronger pressure can be exerted with it than when it is carried by the thread-guide as is the case in the former process already mentioned. In fact, in the latter, the crushing punch is integral with the threadguide, which limits the strength of the pressure which can be exerted by means of this punch.

3. Moreover, the independence of the crushing punch and the very nature of the corresponding anvil make it possible to provide for relievos or moulds on each of these two parts comprising any profile required to make specially shaped linking heads.

This is a substantial advantage as it is thus possible t obtain linking heads with various shapes which allow more eflicient joining than in the case of fasteners made in accordance with the former process already mentioned.

4. As regards the way in which the linking heads are made, it should be noted that the crushing of the thread occurs on the side which will later correspond to the outside face of the fold made.

This peculiarity also helps to obtain linking heads with the precise shape required, which is not always the case when crushing occurs on the inside of the fold formed by the thread.

5. The movement of the thread-guide is very simple, since it is a to-and-fro movement in a direction parallel to the axis of the toothed plate.

Moreover, the crushing punch itself has an equally simple to-and-fro movement parallel to one of the spokes of this plate. The simplicity of these movements makes a very high rate of production possible. Now, this is not possible in the former process previously mentioned, which uses a thread-guide with a more complicated movement.

6. Moreover, the device covered by the invention has the advantage of comprising a very simple construction since it is made up of only three main components, i.e.: the toothed plate used to form the spiral, the thread-guide also used as an anvil, and finally the thread-crushing punch.

Having thus described my invention, what I. claimas new and desire to secure by Letters Patent of the United States is:

1. In a process for the production of a continuous row of linking components for a slide fastener, using a plastic thread, which comprises the steps of shaping the plastic thread into a spiral over and between a series of studs by means of a thread-guide, and crushing one of the ends of each whorl of the spiral by means of a punch to form" a linking component while holding the corresponding whorl between the studs, the improvement which consists in that, on the crushing-point side of each whorl, the corresponding portion of the thread is stretched out rectilinearly beyond the crushing point and facing the corresponding side face of the thread-guide, and in that the required point of the thread is then crushed against .the thread-guide which is used as an anvil, the punch used being independent of the other working tools, and the folding back of 5 6 the corresponding portion of the thread being performed 3,268,646 8/ 1966 MacFee 264-285 only after the crushing has been carried out. 3,353,217 11/1967 Bashover 42539l 3,666,853 5/1972 Popovitsch 264-281 References Cited UNITED ST P 5 R. Prlmary Exarnmer 3,152,433 10/1964 Burbank 425-491 X Us (31, X R 3,229,362 1/1966 Yoshida 264281 X 2 4 231, 295

3,255,288 6/1966 Steingruebner 264281 X 

